Protein phosphorylation is a basic regulator of cellular processes. One gene family, the calcium/lipid activated protein kinase C (PKC) encodes at least 11 isotypes. Among these isotypes the y-PKC isotype is the only PKC solely expressed in neurons of the brain and spinal cord. Until the creation of null mutant mice ("knock-outs") that carry a disrupted y-PKC gene, it has been difficult to analyze the role of specific isotypes in behavioral, biochemical, and physiological processes. We have previously demonstrated that y-PKC null mutants are less sensitive to the hypothermia-inducing and sedative-hypnotic effects of alcohol compared to their wild-type littermates. We provide data here showing that y-PKC mutants do not develop tolerance to some of alcohol's effects. Therefore, it appears that the y-isotype of PKC may play a role in the mediation of ethanol's action. The goal of this proposal is to investigate the role of y-PKC in determining behavioral responses to acute and chronic ethanol treatment. In specific aim #1, the y-PKC null mutants will be compared to mice that are either wild-type or heterozygous for the mutations using several measures of initial sensitivity and tolerance. In specific aim #2, transgenic mouse lines over-expressing y-PKC will be created and characterized for initial sensitivity and tolerance to ethanol. A genetic rescue of the y-PKC null mutants will also be performed by a genetic cross between transgenics and null mutants. The results of these studies will establish whether y-PKC plays a role in the pharmacological actions of ethanol that underlie the determination of ethanol sensitivity and tolerance.